Fine-scale turbulent processes: mesoscale stirring and submesoscale instabilities

X. Capet, LOCEAN, IPSL, France

Upper ocean frontal turbulence associated with horizontal length scales on the order of 1-10 km has attracted significant attention recently. Its role in the ocean is still being debated but much progress has been made on the mechanisms at work. A series of ROMS experiments in a periodic channel are presented to illustrate two dominant mechanisms: i) surface density stirring by mesoscale eddies and ii) fine scale instabilities directly energizing the submesoscale range. A particular example of the latter is the Charney instability whose possible relevance in the ocean will also be discussed.